Why do #10 Pilot FA nibs have so many issues compared to #15 FA nibs?

[MythrianXeras]

So I have both a Custom 742 and a 743, both with the FA nib, and while the 743 was pretty much a perfect writer out of the box, the 742 is pretty much useless, constantly hard starting and skipping and making writing an otherwise miserable exercise. I've tried every ink in my collection, including the obscenely wet Private Reserve Tanzanite, and it did pretty much nothing to improve the flow. I've gotten the 2-slit feeds as well from Flexible Nib Factory, and while the 743 went from an already good writer to a phenomenal one that can use pretty much any ink, the 742 only became just slightly more usable, now capable of a few words without skipping/railroading and still borderline unusable for regular writing because of the constant hard-starting. I've ordered a 3-slit FNF feed to see if that might remedy the issue, but I've largely given up on the pen, and from searching the forums and Reddit, this seems to be a pretty common issue with #10 Pilot FA nibs. What exactly is the reason these nibs perform so much worse than their bigger cousins, even for regular writing?

[A Smug Dill]

1 hour ago, MythrianXeras said:

What exactly is the reason these nibs perform so much worse than their bigger cousins, even for regular writing?

 

But what do you mean by “regular writing”? The FA nibs were primarily designed to write in short pen strokes, for kana and kanji in Japanese. Do you have a problem with the ink flow using the FA nib on the Custom Heritage 912, when you ‘print’ in distinct majuscules and minuscules that are not joined cursively?

[dipper]

5 hours ago, MythrianXeras said:

constantly hard starting and skipping

Just checking that we are understanding correctly...

 

"Hard starting" is when the nib tip touches down onto paper and makes no mark at all. Not even a spot of ink. Can occur at the start of any stroke during writing.

 

"Skipping" is when the nib is already in contact with the paper, and ink is flowing as the nib tip slides over the paper, but then during that same pen stroke the ink line breaks. Can occur with any pen if whipped across the whole page width at unreasonable speed, but is a real problem if it keeps happening during normal writing.

 

 

The root causes of those problems can be interlinked and entangled. For example, a three fissure ebonite feed may increase maximum flow rate - curing skipping. But the change of feed also alters the air breathing processes of the pen, possibly changing the static pressure inside the pen and affecting hard starting. And if the nib is physically held in the grip section by a slightly different shaped feed that may alter the tines orientation, changing the tip gap, and affecting hard starting. There are no easy simple answers.

 

When I experience hard starting the first thing that I do is grab a 10x loupe to have a look at the nib tip to observe what is happening.

The pen is in my right hand, writing, and it is hard starting... I do not move the pen.

 

With my left hand I take up a loupe. I lift the pen from the page keeping it nib-tip-down. Use the loupe to look at the ink meniscus at the tip of the tines, with the pen still held point down. (The window behind my desk, or a bright computer screen makes a good background.)

 

Then invert the pen to be nib up. And view the tip again. Note the shifted ink meniscus position.

 

Then return to nib down orientation, and view again. During the previous period held with nib upwards the air breathing system at the back of the feed (usually) allows air to enter the pen body more freely. Viewed nib down, with any ink pressure problem now relieved by the inversion process, look at the tip again.

 

The ink meniscus will usually fall back from the nib tip slightly when held tip up - perhaps half a meniscus width. (Not designed to work upside down!) But if it falls back entirely leaving an empty slit that suggests the tine gap may be too wide.

 

If the ink is not quite at the tip on the first viewing tip down, but then is improved later after inversion, that suggests the pen has an air breathing problem.

 

Most often in my pens it turns out to be a breathing problem due to air locks in narrow necked international cartridges.

 

 

[XYZZY]

That's odd.  I thought that the general consensus was that the #10 FA nibs were better behaved than the #15.  Either way, though, regardless of how excellent Pilot's quality control, there can still be the occasional dud.  Have you consulted the retailer?

[arcfide]

17 hours ago, dipper said:

(Not designed to work upside down!)

 

Are you saying this in general? Most of my well-tuned nibs will write upside down for a while, though drier. 

[dipper]

14 hours ago, arcfide said:

 

Are you saying this in general? Most of my well-tuned nibs will write upside down for a while, though drier. 

 

Many pens will indeed write with the nib pointing upwards.

But no fountain pen has any design features that automatically transfer ink from the back of the ink chamber up to the feed when held nib upwards. The ink available for writing upside-down is only whatever ink was held in the feed at the moment the pen was inverted.

 

You can find a way, if you are a dedicated upside-down writer. ("The daily diary of my life as a Trapeze Artist" 😄).

Using a piston filler pen, or any pen with a plunger converter, you can frequently move the piston/plunger by hand to expell all air and force ink up into the feed, and continue writing upside-down.

 

But none of that has relevance to my passing note - Not designed to write upside down!

There I was simply clarifying that the small movement of the ink meniscus away from the tip when upside-down is not a fault. It is the inevitable result of physics acting on the ink.

The movement can be a diagnostic clue to the underlying cause of a pen not writing well right-way-up.

- - - - - - - - - - - - - -

 

As a separate line of thought, but related to the main topic here (Skipping and Hard Starting)... Many users of well adjusted pens that can manage to write upside-down would confirm your observation that writing upside-down, when possible, is drier.

Sounds simple enough.

The implications are profound though:

 

When upside-down, the feed ink fissures have not become blocked. If ebonite, then the feed is still ebonite when upside down. The number of ink fissures has not changed. The tines slit is still the same width, etc.... Nothing appears to be limiting the flow of ink.   But somehow the pen is now writing dryer.

 

One thing that has changed is the hydrostatic pressure in the ink at the nib tip, at the point of contact with the paper.

The pen writes dry, upside down, because the ink pressure at the nib tip has changed.

 

The implication is that if a pen starts writing dry when held right way up that might be the onset of some "flow problem", but could equally well be caused by an "ink pressure problem".

 

 

 

 

 

[arcfide]

4 hours ago, dipper said:

There I was simply clarifying that the small movement of the ink meniscus away from the tip when upside-down is not a fault.

 

The rule I use when tuning my own pens is that I should have no noticeable meniscus when holding the pen upside down that would prevent the ink from coming into direct content with the paper at the contact point of the nib. If I see a notable meniscus then I generally adjust the pen to remove it. I want there to be sufficient capillary "pressure" or "draw" (I don't know the correct term) to always keep the tip with ink under capillary action alone. 

[dipper]

17 hours ago, arcfide said:

The rule I use when tuning my own pens is that I should have no noticeable meniscus when holding the pen upside down that would prevent the ink from coming into direct content with the paper

That is a sensible option.

Your "rule" could give controlled and repeatable pen performance after adjusting.

 

I don't adjust my pens like that. Why? Because I have different preferences in the pen performance (just for me specifically).

I like my pens to write wet. So very wet that doing a newspaper crossword would risk ink soaking through from the back page to the front page!

My aim when tuning is to maintain a clearly visible open tip tine gap, whilst still achieving reliable ink meniscus contact with paper when the pen is right way up.

 

I think it is useful to everyone, whatever their own personal preferences are for how their pens write, to hear about different reference points that others use when tuning to achieve different prefered end results.

 

Terminology...?

"Capillary draw", "capillary pressure", "capillary action", "The capillary effect" or "capillary process", and "Capillarity" are all terms used in popular and scientific contexts. All are valid and effective terms. I have never been uncertain what the intended meaning is.

 

However, there is one more technical term that is worth sharing. I use it sparingly, because it is not so well known.

"Laplace Pressure".

The ink meniscus surface is under tension ("surface tension"), and that surface may be curved.

Laplace Pressure is the pressure difference between the fluids on either side of the curved meniscus (air one side, ink the other side) that is balanced by the effect of surface tension acting throughout the curved menuscus surface.

 

When adjusting a tine gap to become narrower at the nib tip, that narrowing increases the curvature of the menuscus. Laplace pressure is increased - acting towards the nib tip - so the ink moves closer to the extreme tip. Movement stops when the meniscus reaches the open edge of the tip gap, where the meniscus flattens slightly until a new balance point is established. (With the ink now in prime position to come into contact with paper.)

 

https://en.m.wikipedia.org/wiki/Laplace_pressure

 

https://en.m.wikipedia.org/wiki/Young–Laplace_equation

 

 

[arcfide]

20 hours ago, dipper said:

I don't adjust my pens like that. Why? Because I have different preferences in the pen performance (just for me specifically).

I like my pens to write wet. So very wet that doing a newspaper crossword would risk ink soaking through from the back page to the front page!

My aim when tuning is to maintain a clearly visible open tip tine gap, whilst still achieving reliable ink meniscus contact with paper when the pen is right way up.

 

Thanks for sharing your own rule. I am curious whether you prefer to use finer or broader nibs? I suspect that either of our "rules" alone don't really make sense. Rather, they make sense in the context of the type of tipping and grind that we tend to prefer on our pens, together with our intended behavior. 

 

I prefer wetter pens, to be sure, but I also favor being able to use the lightest possible touch and maximizing the consistency and reliability of the first stroke of the pen. My use of some harder papers (Masuya, MD) or more coated papers (Tsubame, LIFE, Clairefontaine) also plays into the picture. I also prefer much broader nibs than is typical (my impression is that EF - M is much more common than B+ or BB Italics). 

 

I think that the combination of my preferences has led to my rule. I've found that it is very easy to get too much baby's bottom on a nib grind of that tipping size, and so I've also gravitated towards grinds that have a hint more feedback because they often have sharper internal edges for the tipping, which helps to ensure that ink flow gets to the paper. If I don't get the ink very, very close to the tip, then my light touch on the pen won't be enough pressure (often, it is less pressure than the weight of the pen) to get the ink to make contact with the papers that don't have as much give or softness to them. Combined with even the slightest bit of rotation and you end up with less than ideal first stroke performance. The best way for me to get as close to the wetness that I want and the reliability of the first stroke is to make the nib slit as wide as I can get away with while still keeping the ink all the way at the tip of the nib when held upside down (nib up). 

 

That's probably why I like Music nibs so much, because the double slit means that you can have a very wide line with very good reliability and very wet writing all at the same time. 

 

I suspect that altering of any of the above usage behaviors would make it possible to relax my tine spacing rule to permit a wider nib slit. That is, I suspect that using finer nib sizes, even a slight bit more pressure (I've confirmed this personally), or slightly softer papers (Tomoe River or Leuchtterm1917 for example), would all allow me to have a wider nib slight and still get reasonably reliable performance. 

[dipper]

On 1/29/2023 at 7:46 PM, arcfide said:

Thanks for sharing your own rule. I am curious whether you prefer to use finer or broader nibs?

I use all sizes from Fine to Broad and also Fude nibs.

Generally tip shaping (if needed) and then adjusting and tuning, to give my preferred results, goes pretty easily.

 

Problems found, occasionally, that can occur with any nib tip size, are that I cannot get the ink to reliably sit at the extreme tip of the nib slit without making the slit narrower - and though the pen would then write reliably it would write too dry for my taste. In those cases I usually decide that the overall feed and breather system etc cannot be adjusted (by me) to perform as desired by adjusting the nib and nib/feed fit alone. Not wishing to mess with modifying the back-end of feeds, unless there is clear damage or blockage to be fixed, I then modify the ink properties instead.

A spot of dishwasher rinse-aid (anionic surfactant) added to a fill of ink does wonders!

 

Two types of nib that have defeated me...

 

Sailor DeMannen Fude nib. Untipped. Bought new, but used so much that the toe of the nib became worn down to a sharp edged knife blade! Tried to reshape that as a mini-fude. Result is just horrid. Not worth any more effort as I have discovered the Duke 209 fude pen is so much better.

 

Parker UK Duofold, nib dated 1954, a semi-flex italic nib. A beautuful writing italic when it is working, but goes out of adjustment so frequently that it is currently "retired". I suspect the plastic grip section has distorted and its only hope is to ream out the section for a more stable fit.

I have read that achieving good ink to paper contact in an italic nib is more difficult than with other tip forms. Add in a flexy nib and an aged wonky plastic grip section - that is all more than I can handle!

[Kgbenson]

So where does the 912 fit into all this.  I am looking to make the FA nib my next purchase, and am waffling between a 743 and a 912, likely either would get an ebonite feed as well.  Any thoughts on which might be a wiser choice for someone who is not a skilled nib adjuster?

 

Keith

[Lithium466]

The 912 has a #10 nib. No complain on mine. 

[WRBNYC]

On 1/28/2023 at 5:36 PM, dipper said:

That is a sensible option.

Your "rule" could give controlled and repeatable pen performance after adjusting.

 

I don't adjust my pens like that. Why? Because I have different preferences in the pen performance (just for me specifically).

I like my pens to write wet. So very wet that doing a newspaper crossword would risk ink soaking through from the back page to the front page!

My aim when tuning is to maintain a clearly visible open tip tine gap, whilst still achieving reliable ink meniscus contact with paper when the pen is right way up.

 

I think it is useful to everyone, whatever their own personal preferences are for how their pens write, to hear about different reference points that others use when tuning to achieve different prefered end results.

 

Terminology...?

"Capillary draw", "capillary pressure", "capillary action", "The capillary effect" or "capillary process", and "Capillarity" are all terms used in popular and scientific contexts. All are valid and effective terms. I have never been uncertain what the intended meaning is.

 

However, there is one more technical term that is worth sharing. I use it sparingly, because it is not so well known.

"Laplace Pressure".

The ink meniscus surface is under tension ("surface tension"), and that surface may be curved.

Laplace Pressure is the pressure difference between the fluids on either side of the curved meniscus (air one side, ink the other side) that is balanced by the effect of surface tension acting throughout the curved menuscus surface.

 

When adjusting a tine gap to become narrower at the nib tip, that narrowing increases the curvature of the menuscus. Laplace pressure is increased - acting towards the nib tip - so the ink moves closer to the extreme tip. Movement stops when the meniscus reaches the open edge of the tip gap, where the meniscus flattens slightly until a new balance point is established. (With the ink now in prime position to come into contact with paper.)

 

https://en.m.wikipedia.org/wiki/Laplace_pressure

 

https://en.m.wikipedia.org/wiki/Young–Laplace_equation

 

 

This is so interesting! Thanks for sharing.

[effrafax]

On 2/14/2023 at 2:54 AM, Kgbenson said:

... between a 743 and a 912

 

The main difference between the two nib sizes are that the #15 (on 743) is stiffer than the #10 (on 912/742), which seems a little contradictory, but that's how it is.  It takes more pressure to flex the #15, but it has a faster snap-back (to me).  You really need to try them both before purchasing, if at all possible, to see which feels best for you and your writing style or intended purpose.

 

[Edit: fix typo.]